linux-kernel - Re: [PATCH v2] rust: sync: require `T: Sync` for `LockedBy::access`

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CANiq72mTnHNTzCX_FtSp53cjUj0rF-yCAoShN77RotMcz0L4Hw@mail.gmail.com>
Date: Thu, 26 Sep 2024 23:18:41 +0200
From: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To: Alice Ryhl <aliceryhl@...gle.com>, Boqun Feng <boqun.feng@...il.com>
Cc: Miguel Ojeda <ojeda@...nel.org>, Gary Guo <gary@...yguo.net>, 
	Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <benno.lossin@...ton.me>, Andreas Hindborg <a.hindborg@...sung.com>, 
	Trevor Gross <tmgross@...ch.edu>, Martin Rodriguez Reboredo <yakoyoku@...il.com>, rust-for-linux@...r.kernel.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] rust: sync: require `T: Sync` for `LockedBy::access`

On Sun, Sep 15, 2024 at 4:41 PM Alice Ryhl <aliceryhl@...gle.com> wrote:
>
> The `LockedBy::access` method only requires a shared reference to the
> owner, so if we have shared access to the `LockedBy` from several
> threads at once, then two threads could call `access` in parallel and
> both obtain a shared reference to the inner value. Thus, require that
> `T: Sync` when calling the `access` method.
>
> An alternative is to require `T: Sync` in the `impl Sync for LockedBy`.
> This patch does not choose that approach as it gives up the ability to
> use `LockedBy` with `!Sync` types, which is okay as long as you only use
> `access_mut`.
>
> Cc: stable@...r.kernel.org
> Fixes: 7b1f55e3a984 ("rust: sync: introduce `LockedBy`")
> Signed-off-by: Alice Ryhl <aliceryhl@...gle.com>

Applied to `rust-fixes` with Boqun's Suggested-by -- thanks!

Cheers,
Miguel